Are התאמן and התעמל synonyms?
צריכות? need or must?
"Need to" and "Must" are synonyms in English.
Although "must" is a little stronger than "need to" in English
Yes, that is true. But they are still synonyms.
"must" would be correct in English.
Is the present tense of
covered in this section? I don't recall seeing it.
אַתָּה צָרִיךְ לְהִתְעַמֵּל לְהִתְעַלֵּם מִמִּשְׁפָּטִים עִם פּוֹעַל לְהִתְעַמֵּל. :-)